Traffic and mobility aware virtual access points

ABSTRACT

In one embodiment, a supervisory device in a network classifies mobility and traffic characteristics of a first node in the network. The supervisory device identifies wireless channels supported by access points (APs) in the network. The supervisory device selects one of the wireless channels for use by the first node based on the classified mobility and traffic characteristics of the first node. The supervisory device forms a first virtual access point (VAP) for the first node on the selected wireless channel. A plurality of the access points (APs) in the network that support the selected channel are mapped to the first VAP as part of a VAP mapping. The first node treats the APs in the VAP mapping as a single AP for purposes of communicating with the network.

TECHNICAL FIELD

The present disclosure relates generally to computer networks, and, more particularly, to traffic and mobility aware virtual access points (VAPs).

BACKGROUND

The Internet of Things (IoT) is the internetworking of devices or objects (a.k.a., “things”, e.g., sensors, actuators, nodes, vehicles, etc.) that collect and exchange data, control objects, and process data. Many IoT networks are formed on low-power lossy networks (LLNs), and utilize carrier sense multiple access with collision avoidance (CSMA/CA) techniques. CSMA/CA, notably, is a communication technique that uses carrier sensing, where nodes attempt to avoid collisions by transmitting only when the channel is sensed to be “idle.”

In general, deterministic routing concerns ensuring that messages (e.g., packets) definitively arrive at a destination at a specific time or within a specified time range. However, implementing determinism in hub-and-spoke IoT models, particularly with CSMA/CA, faces a litany of drawbacks, such as overwhelming a server with multiple copies of traffic, excessive delay, surges in latency, and unacceptable frame loss.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments herein may be better understood by referring to the following description in conjunction with the accompanying drawings in which like reference numerals indicate identically or functionally similar elements, of which:

FIG. 1 illustrates an example communication network;

FIG. 2 illustrates an example network device/node;

FIGS. 3A-3D illustrate an example of virtual access point (VAP) formation;

FIGS.4A-4B illustrate an example of the operation of a VAP;

FIGS. 5A-5C illustrate an example of adjusting a VAP mapping;

FIG. 6 illustrates an example of forming a channel plan based on mobility and traffic characteristics;

FIGS. 7A-7C illustrate the mapping of an AP to a VAP for a client node based on the mobility and traffic characteristics of the node;

FIGS. 8A-8B illustrate another example of mapping an AP to a VAP for a client node based on the mobility and traffic characteristics of the node; and

FIG. 9 illustrates an example simplified procedure for forming a traffic and mobility aware VAP.

DESCRIPTION OF EXAMPLE EMBODIMENTS Overview

According to one or more embodiments of the disclosure, a supervisory device in a network classifies mobility and traffic characteristics of a first node in the network. The supervisory device identifies wireless channels supported by access points (APs) in the network. The supervisory device selects one of the wireless channels for use by the first node based on the classified mobility and traffic characteristics of the first node. The supervisory device forms a first virtual access point (VAP) for the first node on the selected wireless channel. A plurality of the access points (APs) in the network that support the selected channel are mapped to the first VAP as part of a VAP mapping. The first node treats the APs in the VAP mapping as a single AP for purposes of communicating with the network.

Description

A computer network is a geographically distributed collection of nodes interconnected by communication links and segments for transporting data between end nodes, such as personal computers and workstations, or other devices, such as sensors, etc. Many types of networks are available, ranging from local area networks (LANs) to wide area networks (WANs). LANs typically connect the nodes over dedicated private communications links located in the same general physical location, such as a building or campus. WANs, on the other hand, typically connect geographically dispersed nodes over long-distance communications links, such as common carrier telephone lines, optical lightpaths, synchronous optical networks (SONET), synchronous digital hierarchy (SDH) links, or Powerline Communications (PLC), and others. Other types of networks, such as field area networks (FANs), neighborhood area networks (NANs), personal area networks (PANs), etc. may also make up the components of any given computer network.

In various embodiments, computer networks may include an Internet of Things network. Loosely, the term “Internet of Things” or “IoT” (or “Internet of Everything” or “IoE”) refers to uniquely identifiable objects (things) and their virtual representations in a network-based architecture. In particular, the IoT involves the ability to connect more than just computers and communications devices, but rather the ability to connect “objects” in general, such as lights, appliances, vehicles, heating, ventilating, and air-conditioning (HVAC), windows and window shades and blinds, doors, locks, etc. The “Internet of Things” thus generally refers to the interconnection of objects (e.g., smart objects), such as sensors and actuators, over a computer network (e.g., via IP), which may be the public Internet or a private network.

Often, IoT networks operate within a shared-media mesh networks, such as wireless or PLC networks, etc., and are often on what is referred to as Low-Power and Lossy Networks (LLNs), which are a class of network in which both the routers and their interconnect are constrained. That is, LLN devices/routers typically operate with constraints, e.g., processing power, memory, and/or energy (battery), and their interconnects are characterized by, illustratively, high loss rates, low data rates, and/or instability. IoT networks are comprised of anything from a few dozen to thousands or even millions of devices, and support point-to-point traffic (between devices inside the network), point-to-multipoint traffic (from a central control point such as a root node to a subset of devices inside the network), and multipoint-to-point traffic (from devices inside the network towards a central control point).

Fog computing is a distributed approach of cloud implementation that acts as an intermediate layer from local networks (e.g., IoT networks) to the cloud (e.g., centralized and/or shared resources, as will be understood by those skilled in the art). That is, generally, fog computing entails using devices at the network edge to provide application services, including computation, networking, and storage, to the local nodes in the network, in contrast to cloud-based approaches that rely on remote data centers/cloud environments for the services. To this end, a fog node is a functional node that is deployed close to fog endpoints to provide computing, storage, and networking resources and services. Multiple fog nodes organized or configured together form a fog system, to implement a particular solution. Fog nodes and fog systems can have the same or complementary capabilities, in various implementations. That is, each individual fog node does not have to implement the entire spectrum of capabilities. Instead, the fog capabilities may be distributed across multiple fog nodes and systems, which may collaborate to help each other to provide the desired services. In other words, a fog system can include any number of virtualized services and/or data stores that are spread across the distributed fog nodes. This may include a master-slave configuration, publish-subscribe configuration, or peer-to-peer configuration.

Low power and Lossy Networks (LLNs), e.g., certain sensor networks, may be used in a myriad of applications such as for “Smart Grid” and “Smart Cities.” A number of challenges in LLNs have been presented, such as:

1) Links are generally lossy, such that a Packet Delivery Rate/Ratio (PDR) can dramatically vary due to various sources of interferences, e.g., considerably affecting the bit error rate (BER);

2) Links are generally low bandwidth, such that control plane traffic must generally be bounded and negligible compared to the low rate data traffic;

3) There are a number of use cases that require specifying a set of link and node metrics, some of them being dynamic, thus requiring specific smoothing functions to avoid routing instability, considerably draining bandwidth and energy;

4) Constraint-routing may be required by some applications, e.g., to establish routing paths that will avoid non-encrypted links, nodes running low on energy, etc.;

5) Scale of the networks may become very large, e.g., on the order of several thousands to millions of nodes; and

6) Nodes may be constrained with a low memory, a reduced processing capability, a low power supply (e.g., battery).

In other words, LLNs are a class of network in which both the routers and their interconnect are constrained: LLN routers typically operate with constraints, e.g., processing power, memory, and/or energy (battery), and their interconnects are characterized by, illustratively, high loss rates, low data rates, and/or instability. LLNs are comprised of anything from a few dozen and up to thousands or even millions of LLN routers, and support point-to-point traffic (between devices inside the LLN), point-to-multipoint traffic (from a central control point to a subset of devices inside the LLN) and multipoint-to-point traffic (from devices inside the LLN towards a central control point).

An example implementation of LLNs is an “Internet of Things” network. Loosely, the term “Internet of Things” or “IoT” may be used by those in the art to refer to uniquely identifiable objects (things) and their virtual representations in a network-based architecture. In particular, the next frontier in the evolution of the Internet is the ability to connect more than just computers and communications devices, but rather the ability to connect “objects” in general, such as lights, appliances, vehicles, HVAC (heating, ventilating, and air-conditioning), windows and window shades and blinds, doors, locks, etc. The “Internet of Things” thus generally refers to the interconnection of objects (e.g., smart objects), such as sensors and actuators, over a computer network (e.g., IP), which may be the Public Internet or a private network. Such devices have been used in the industry for decades, usually in the form of non-IP or proprietary protocols that are connected to IP networks by way of protocol translation gateways. With the emergence of a myriad of applications, such as the smart grid advanced metering infrastructure (AMI), smart cities, and building and industrial automation, and cars (e.g., that can interconnect millions of objects for sensing things like power quality, tire pressure, and temperature and that can actuate engines and lights), it has been of the utmost importance to extend the IP protocol suite for these networks.

FIG. 1 is a schematic block diagram of an example simplified computer network 100 illustratively comprising nodes/devices at various levels of the network, interconnected by various methods of communication. For instance, the links may be wired links or shared media (e.g., wireless links, PLC links, etc.) where certain nodes, such as, e.g., routers, sensors, computers, etc., may be in communication with other devices, e.g., based on connectivity, distance, signal strength, current operational status, location, etc.

Specifically, as shown in the example network 100, three illustrative layers are shown, namely the cloud 110, fog 120, and IoT device 130. Illustratively, the cloud 110 may comprise general connectivity via the Internet 112, and may contain one or more datacenters 114 with one or more centralized servers 116 or other devices, as will be appreciated by those skilled in the art. Within the fog layer 120, various fog nodes/devices 122 (e.g., with fog modules, described below) may execute various fog computing resources on network edge devices, as opposed to datacenter/cloud-based servers or on the endpoint nodes 132 themselves of the IoT layer 130. Data packets (e.g., traffic and/or messages sent between the devices/nodes) may be exchanged among the nodes/devices of the computer network 100 using predefined network communication protocols such as certain known wired protocols, wireless protocols, PLC protocols, or other shared-media protocols where appropriate. In this context, a protocol consists of a set of rules defining how the nodes interact with each other.

Those skilled in the art will understand that any number of nodes, devices, links, etc. may be used in the computer network, and that the view shown herein is for simplicity. Also, those skilled in the art will further understand that while the network is shown in a certain orientation, the network 100 is merely an example illustration that is not meant to limit the disclosure.

Data packets (e.g., traffic and/or messages) may be exchanged among the nodes/devices of the computer network 100 using predefined network communication protocols such as certain known wired protocols, wireless protocols (e.g., IEEE Std. 802.15.4, Wi-Fi, Bluetooth®, DECT-Ultra Low Energy, LoRa, etc.), PLC protocols, or other shared-media protocols where appropriate. In this context, a protocol consists of a set of rules defining how the nodes interact with each other.

FIG. 2 is a schematic block diagram of an example node/device 200 that may be used with one or more embodiments described herein, e.g., as any of the nodes or devices shown in FIG. 1 above or described in further detail below. The device 200 may comprise one or more network interfaces 210 (e.g., wired, wireless, PLC, etc.), at least one processor 220, and a memory 240 interconnected by a system bus 250, as well as a power supply 260 (e.g., battery, plug-in, etc.).

The network interface(s) 210 include the mechanical, electrical, and signaling circuitry for communicating data over links 105 coupled to the network 100. The network interfaces may be configured to transmit and/or receive data using a variety of different communication protocols. Note, further, that the nodes may have two different types of network connections 210, e.g., wireless and wired/physical connections, and that the view herein is merely for illustration. Also, while the network interface 210 is shown separately from power supply 260, for PLC the network interface 210 may communicate through the power supply 260, or may be an integral component of the power supply. In some specific configurations the PLC signal may be coupled to the power line feeding into the power supply.

The memory 240 comprises a plurality of storage locations that are addressable by the processor 220 and the network interfaces 210 for storing software programs and data structures associated with the embodiments described herein. Note that certain devices may have limited memory or no memory (e.g., no memory for storage other than for programs/processes operating on the device and associated caches). The processor 220 may comprise hardware elements or hardware logic adapted to execute the software programs and manipulate the data structures 245. Operating system 242, portions of which is typically resident in memory 240 and executed by the processor, functionally organizes the device by, inter alia, invoking operations in support of software processes and/or services executing on the device. These software processes and/or services may comprise routing process/services 244 and an illustrative virtual access point (VAP) process 248, as described herein. Note that while VAP process 248 is shown in centralized memory 240, alternative embodiments provide for the process to be specifically operated within the network interfaces 210, such as a component of a MAC layer (e.g., process 248 a).

It will be apparent to those skilled in the art that other processor and memory types, including various computer-readable media, may be used to store and execute program instructions pertaining to the techniques described herein. Also, while the description illustrates various processes, it is expressly contemplated that various processes may be embodied as modules configured to operate in accordance with the techniques herein (e.g., according to the functionality of a similar process). Further, while the processes have been shown separately, those skilled in the art will appreciate that processes may be routines or modules within other processes.

In general, VAP process 248 includes computer executable instructions that, when executed by processor(s) 220, cause device 200 to perform operations regarding the formation, adjustment, and operation of a VAP within the network. These operations are described in greater detail below. In some embodiments, process 248 may employ any number of machine learning techniques, to perform these operations. In general, machine learning is concerned with the design and the development of techniques that receive empirical data as input (e.g., data regarding the performance/characteristics of the network) and recognize complex patterns in the input data. For example, some machine learning techniques use an underlying model M, whose parameters are optimized for minimizing the cost function associated to M, given the input data. For instance, in the context of classification, the model M may be a straight line that separates the data into two classes (e.g., labels) such that M=a*x+b*y+c and the cost function is a function of the number of misclassified points. The learning process then operates by adjusting the parameters a,b,c such that the number of misclassified points is minimal. After this optimization/learning phase, process 248 can use the model M to classify new data points, such as information regarding the performance/characteristics associated with an established VAP or its underlying APs, to adjust the VAP, accordingly. Often, M is a statistical model, and the cost function is inversely proportional to the likelihood of M, given the input data.

In various embodiments, VAP process 248 may employ one or more supervised, unsupervised, or semi-supervised machine learning models to analyze traffic flow data. Generally, supervised learning entails the use of a training dataset, which is used to train the model to apply labels to the input data. For example, the training data may include sample network data that may be labeled simply as representative of a “good connection” or a “bad connection.” On the other end of the spectrum are unsupervised techniques that do not require a training set of labels. Notably, while a supervised learning model may look for previously seen network data that has been labeled accordingly, an unsupervised model may instead look to whether there are sudden changes in the performance of the network and/or the VAP. Semi-supervised learning models take a middle ground approach that uses a greatly reduced set of labeled training data.

Example machine learning techniques that process 248 can employ may include, but are not limited to, nearest neighbor (NN) techniques (e.g., k-NN models, replicator NN models, etc.), statistical techniques (e.g., Bayesian networks, etc.), clustering techniques (e.g., k-means, mean-shift, etc.), neural networks (e.g., reservoir networks, artificial neural networks, etc.), support vector machines (SVMs), logistic or other regression, Markov models or chains, principal component analysis (PCA) (e.g., for linear models), multi-layer perceptron (MLP) ANNs (e.g., for non-linear models), replicating reservoir networks (e.g., for non-linear models, typically for time series), random forest classification, or the like.

The performance of a machine learning model can be evaluated in a number of ways based on the number of true positives, false positives, true negatives, and/or false negatives of the model. For example, the false positives of the model may refer to the number of times the model incorrectly labeled a connection as bad. Conversely, the false negatives of the model may refer to the number of connections that the model labels as ‘good,’ but are, in fact, of poor quality to the user or endpoint node. True negatives and positives may refer to the number of times the model correctly classifies a connection as good or bad, respectively. Related to these measurements are the concepts of recall and precision. Generally, recall refers to the ratio of true positives to the sum of true positives and false negatives, which quantifies the sensitivity of the model. Similarly, precision refers to the ratio of true positives the sum of true and false positives. In some cases, process 248 may also use reinforcement learning techniques which generally act to use feedback about the ML predictions, to adjust the underlying model. For example, an indication of a false positive from an expert (e.g., a supervisory system or user) may be used to adjust the underlying model, to avoid such predictive mistakes in the future.

As mentioned above, various protocols have been established for the IoT, including, in particular, various “hub-and-spoke” models, such as Bluetooth Low Energy, DECT-Ultra Low Energy, IEEE 802.15.4 (with no meshing), and Low Power Wi-Fi. However, there is also a lack of determinism in these models due to prevalent use of carrier sense multiple access with collision avoidance (CSMA/CA) for wireless communications. Notably, deterministic networking requires that the worst-case data loss and latency should be guaranteed in a consistent fashion as multiple services are deployed on a common converged network infrastructure. This determinism is key to many applications, such as safety and process control. To complicate matters further, considering the vast amounts of devices that are currently being installed in various IoT networks, an important constraint to be placed on any solution is that changes at the end device (e.g., IoT device/thing) should not be necessary. This would also enable connection of legacy devices, thereby addressing a much wider market of applicability.

Virtual Access Point (VAP) Formation

The techniques herein introduce a methodology that can be used with existing IoT infrastructure to implement a virtual access point (VAP) that is unique to a given IoT node. In general, the VAP is a logical entity that appears to the endpoint node as a normal AP to which the node associates as normal. In practice, however, the VAP is physically distributed over a number of APs surrounding the device. In another aspect, a supervisory device in the network may control the AP membership in the VAP, such as by transferring AP membership in the network while the node moves and without requiring the node to roam. In further aspects, a machine learning model of the supervisory device may oversee the VAP and adjust the VAP mapping, accordingly. Such a machine learning model may reside in the supervisory device (e.g., controller, cloud service, etc.) in a centralized mode, or in a distributed manner across the APs. Depending on the traffic criticality, more or less of those APs may copy a given frame received from the endpoint node to the supervisory device.

Illustratively, the techniques described herein may be performed by hardware, software, and/or firmware, such as in accordance with virtual access point process 248, which may include computer executable instructions executed by processor 220 (or independent processor of interfaces 210) to perform functions relating to the techniques described herein. In particular, VAP process 248 may be a component of an IoT device, a cloud device, or any other participating device for the techniques described herein.

Specifically, according to one or more embodiments of the disclosure, a supervisory device in a network receives from a plurality of APs in the network data regarding a network availability request broadcast by a node seeking to access the network and received by the APs in the plurality. The supervisory device uniquely associates the node with a VAP for the node and forms a VAP mapping between the VAP for the node and a set of the APs in the plurality selected based on the received data regarding the network availability request. One of the APs in the mapping is designated as a primary access point for the node. The supervisory device instructs the primary AP to send a network availability response to the node that includes information for the VAP. The node uses the information for the VAP to access the network via the set of APs in the VAP mapping.

Operationally, the techniques herein specify an architecture and protocol between a supervisory device in a network (e.g., a controller, such as a network server) and a plurality of network access points (APs). The supervisory device may be configured for use with any of the technologies, noted above. Note that the techniques herein illustratively place a number of functions in the supervisory device, such as components hosting Machine Learning (ML) processes, also referred to as “learning machines”) that are mostly technology-independent. In some embodiments, these processes may be implemented in a distributed manner (e.g., across different APs), in which case the collective set of APs may be viewed as the supervisory device.

More specifically, the techniques herein enable the formation and use of a VAP that appears to always be “near” an endpoint node, so that quality of transmission and PHY speed can be maintained. A VAP may be instantiated within a set of APs around the node, and the set may vary automatically under the control of the supervisory device (e.g., a controller hosting a machine learning model) within the infrastructure. Thus, the device never needs to make a decision of roaming, which is a paradigm change in Wi-Fi and other wireless networks. Also, since multiple APs can receive a same packet at a same time with unrelated probabilities, the overall chances of reception are increased and delays related to retries are reduced, thus helping with determinism.

Generally, a VAP may include any number of physical APs in the network that are placed in groups of equivalence, all using the same channel and security settings. When a node (e.g., a STA) associates with the network, the supervisory device (e.g., controller) may select a set of APs that together form a VAP for the associated node. The set may be changed as the node moves. In this way, the endpoint node may experience a constant service from the network and does not roam. For joining, the node may interact with one of the APs (e.g., a primary networking AP) and may use a unique network identifier associated with the VAP, such as a unique service set identifier (SSID), a PAN-ID, or the like, that the node uses to access the network. The supervisory device may also optimize the set of APs based on an objective function and on the observed traffic in the network. Diversity is obtained because multiple members of the VAP may receive the same packet from the node, with relatively independent chances of success.

The illustrative VAP protocol described herein also integrates well with deterministic networking (DetNet). In particular, the VAP protocol enables multiple APs to receive a packet from an endpoint node at the same time, creating a natural replication mechanism in which multiple copies of a same packet may be captured, each by a different AP participating in the VAP assigned to the node. Those APs may be connected over different networks and the packet may circulate to the router or the final destination over segregated paths. DetNet elimination may then be used to eliminate duplicate copies, if any. The VAP protocol herein also leverages various networking techniques (e.g., Wi-Fi, controllers, ML processes, etc.), to improve the user experience while maintaining compatibility with the existing network standards and existing endpoint nodes, by creating a virtual AP that is always there and always optimized so the node never tries to roam.

FIGS. 3A-3D illustrate an example of virtual access point (VAP) formation, according to various embodiments. As shown in FIG. 3A, assume that there exists a portion 300 of a network that includes a plurality of APs 302 (e.g., APs 302 a-302 j) that are located in different physical locations through an area (e.g., a building, campus, etc.). APs 302 may be in communication with a supervisory device 304 in the network, such as a wireless controller, other networking device, or, alternatively, a remote device, such as a server located in a data center or cloud computing environment.

Now, assume that a node 306 is attempting to access the network. In such a case, node 306 may broadcast a network availability request 308. The specific format of request 308 may be a function of the specific wireless protocols in use by the network. For example, in the case of 802.11 networks, availability request 308 may be a probe request. As would be appreciated, from the standpoint of node 306, the expected availability response would include an identifier for the available network, such as the SSID of the Wi-Fi network. Reception of availability request 308 by any of APs 302 may trigger the formation of a VAP for node 306, in various embodiments. In further embodiments, a VAP may also be formed at any time after node 306 associates with the network.

In many network implementations, a plurality of APs 302 may receive the broadcast network availability request 308 from node 306, with varying results. Notably, APs 302 within range of node 306 may, by virtue of receiving request 308, capture data regarding request 308, including the contents of request 308 and other characteristics of the received request 308 such as, but not limited to, a link quality indicator (LQI), a signal to noise ratio (SNR), or received signal strength indicator (RSSI), or the like. For example, as shown, AP 302 f, which is physically located closest to node 306, may determine that the quality of the received request 308 is “excellent.” Similarly, APs 302 g, 302 c, and 302 e may determine that the quality of the received request 308 is “good,” “fair,” and “poor,” respectively.

In various embodiments, rather than simply responding to request 308 with the requisite information needed for node 306 to associate with the network, the receiving APs 302 may instead report the captured data regarding request 308 to supervisory device 304. In particular, as shown in FIG. 3B, APs 302 c, 302 e, 302 f, and 302 g may send the data 310 regarding the received network availability request 308 from node 306 to supervisory device 304, thereby triggering the formation of a VAP for node 306. Data 310 may include, for example, the identity of the sending AP 302 that received request 308, a MAC address or other networking device identifier for node 306, security status information, and/or at least one metric of the quality of the communication with the node (e.g., signal strength, signal to noise ratio, signal quality, etc.).

In FIG. 3C, the supervisory device 304 may create a virtual AP (VAP) that is unique to node 306. In general, the VAP may be mapped to any number of APs 306 selected by supervisory device 304 based in part on the data 310 regarding the availability request 308 received by the various APs 302. In other words, the VAP may be a logical construct that is distributed over multiple APs 302. For example, even though APs 302 c, 302 e, 302 f, and 302 g received association request 308 from node 306, supervisory device 306 may determine that the set of APs 302 in the VAP mapping for node 306 should only include APs 302 c, 302 f, and 302 g, based on the quality of the received request 308 (e.g., AP 302 e may be excluded from the VAP based on the poor quality of the received broadcast signal).

In addition to selecting the VAP member APs 302, supervisory device 304 may also designate one of the selected APs 302 as the primary AP 302 for the VAP. For example, based on data 310 regarding the availability request 308 sent by node 306, supervisory device 304 may determine that AP 302 f has the best signal quality and should be the primary AP within the VAP for node 306. In turn, as shown in FIG. 3C, supervisory device 304 may send instructions 312 to the selected APs 302 c, 302 f, and 302 g that include information regarding the VAP. For example, instructions 312 may instruct the selected APs 302 c, 302 f, and 302 g to belong to the VAP for node 306, as identified initially by MAC address of node 306 and, as soon as it is available, by security token, and/or other cryptographic methods.

To implement the VAP in the network, supervisory device 304 may employ a VAP protocol, in order to exchange configuration and data packets with the APs 302. This protocol may be seen as an extension to existing protocols, such as Lightweight Access Point Protocol (LWAPP) and Control and Provisioning of Wireless Access Points (CAPWAP), or may be specified as a new protocol. For example, the exchanges of data 310 and instructions 312 may use this VAP protocol.

As shown in FIG. 3D, once the VAP has been generated and APs 302 c, 302 f, and 302 g selected for mapping to the VAP, the primary AP 302 f may send a network availability response 314 back to node 306. For example, response 314 may be a unicast probe response that has the same information as a beacon frame. In various embodiments, response 314 sent by primary AP 302 f to node 306 may also include a unique network identifier associated with the VAP. For example, response 314 may include an SSID or PAN-ID generated by supervisory device 304 specifically for use with the VAP. In turn, node 306 may use the received response 314 to associate with the network, as it would under normal conditions. From the standpoint of node 306, it is associating with the network normally via AP 302 f and may remain unaware of the existence of its associated VAP.

FIGS.4A-4B illustrate an example of the operation of a VAP after formation, according to various embodiments. Continuing the examples of FIGS. 3A-3D, when forming the VAP for node 306, supervisory device 304 may also build an ordered list of the other APs 302 in the VAP mapping and conveyed to the selected APs 302 via instructions 312. In general, the ordered list may be used to add special diversity and improve the chances of a successful reception versus a retry from a given AP 302 that has already failed once. For example, as shown in FIG. 4A, assume that primary AP 302 f has sent a message to node 306, but that message has not been acknowledged by node 306. Under normal circumstances, AP 302 f would then attempt to retry sending the message again to node 306. However, according to various embodiments, as shown in FIG. 4B, AP 306 g may instead resend the message 402 to node 306. Because the resend is sent from a different AP, the added spatial diversity increases the chances that the resent message 402 is received and acknowledged by node 306.

In various embodiments, learning machines may play a key role in the assignment of APs to a VAP and/or in the adjustment of an existing VAP. For example, such a learning machine may be trained to select APs 302 for inclusion in a given VAP based on a location estimation for the corresponding node (e.g., from data 310) and/or the desired optimization for the traffic expected from that type of node. For example, the location of node 306 may be derived from a Time Difference of Arrival value (TDOA or DTOA) and/or using triangulation between different APs 302.

Such a traffic optimization may be based on a history of traffic for the type of node, in some cases. As would be appreciated, the type of approach taken by the learning machine(s) may also vary with the specific objective function for the traffic and node type. For example, assume that node 306 is a particular type of telepresence device and that video traffic from similar devices has required a certain degree of network performance (e.g., in terms of drops, delay, jitter, etc.). In such a case, the learning machine may use its model for this node type, as well as any necessary metrics from the APs 302 in the network, to select an appropriate VAP mapping to satisfy the objective function. Note that the objective function will also dramatically influence the set of metrics to be gathered from APs after the scanning phase but also during the lifetime of a VAP. Indeed, according to the objective function, the set of required features, in machine learning terms, may vary, and the frequency of AP selection for the VAP will also vary.

FIGS. 5A-5C illustrate an example of adjusting a VAP mapping, according to various embodiments. Even after formation of a VAP for a given node, supervisory device 304 may continue to monitor and adjust the VAP, in order to ensure that the objective function of the corresponding machine learning model for node 306 continues to be met. To do so, the following message types are introduced herein as part of the VAP protocol:

1.) VAP commands sent by the learning machine to APs 302, to gather metrics of interest (e.g., network characteristics/statistics), report the VAP group membership, etc.

2.) VAP metrics sent by the responding APs 302 to the learning machine and used by the objective function to compute the VAP membership (e.g., based on signal/noise ratio, signal strength, etc.).

3.) VAP stats reports sent by APs 302 to the learning machine and used to evaluate the VAP efficiency. Such stats reports may be used to gather statistical data used by the learning machine to determine the “efficiency” of the VAP group, which can be used by the learning machine to consistently adjust the VAP according to an objective function.

4.) Learning machine stats sent by learning machine to a user interface, to report objective function efficiency results.

In various embodiments, for purposes of collecting network metrics/characteristics and VAP stats from APs 302, supervisory device 304 may occasionally increase or otherwise adjust the APs in the VAP mapping. For example, as shown in FIG. 5A, supervisory device 304 may include AP 302 e in the VAP mapping for purposes of data collection after formation of the VAP (e.g., via an instruction 312, even though AP 302 e was not included in the original VAP mapping. This allows AP 302 e to collect and report information that would not otherwise be possible using the original APs of the VAP. For example, by changing the set of APs, the learning machine can change the TDOA listeners and optimize the distance estimation, e.g., by adding APs while doing a measure, or triangulating between different sets of APs. Such collected information 502 may be reported to supervisory device 304, either on a push or pull basis. After the data collection, supervisory device 304 may opt to revert the VAP mapping back to its previous membership or make further adjustments to the AP memberships, accordingly.

As shown in FIG. 5B, supervisory device 304 may also convey data regarding the performance of the VAP (e.g., the objective function, etc.) to a user interface 504 for review by a user. In some embodiments, the learning machine may also use reinforcement learning to adjust its model for node 306 and make changes to the VAP mapping, accordingly. In such a case, the user of interface 504 (e.g., an admin device, etc.) may provide feedback 506 to the learning machine about the VAP efficiency, which is then used by the LM to adjust the strategy adopted to compute the VAP mapping.

Based on the captured network characteristics from the APs, the performance statistics for the VAP itself, and/or user feedback, the machine learning process may adjust the VAP by changing the APs in the VAP mapping. For example, as shown in FIG. 5C, assume that node 506 has move to a new physical location and is now in closer proximity to APs 302 e and 302 g. In such a case, supervisory device 504 may select a new set of APs 302 for the VAP of node 306 and send out corresponding instructions to the APs. Notably, as shown, supervisory device 304 may select a new set of APs for the VAP of node 306 that includes APs 302 e, 302 f, and 302 g, with 302 g now designated as the primary AP.

Thus, the generated VAP may add spatial diversity to any CSMA/CA LLN, in a manner somewhat akin to that of the LoRa model. However, in contrast to the techniques herein, LoRa uses different MAC operations and does not support the faster speeds of the components (e.g., PHY) used in today's IoT network devices. Additionally, LoRa does not support the association process, the use of identities (e.g., PAN-ID or SSID), and the automatic repeat request (ARQ) process for acknowledgement and retry, which are supported using the techniques herein. Further, LoRa does not support multicast communications, either.

As noted above, the VAP techniques herein allows a virtual AP to be allocated to a given node, whereby the VAP is impersonated by a collection of APs located around the node and each AP has one or more available radio chains. The collection APs in the VAP mapping is selected by a controller/supervisory device that determines the best set of APs/radio chains for a given client based on the client's signal, location, etc.

Typically, a physical AP today has multiple radio chains, which allows for greater bandwidth, as well as beam forming. In particular, newer Wi-Fi APs leverage the concept of Multiple Ins, Multiple Outs (MIMO) in which multiple radio chains operate in parallel to increase the amount of data that any radio could transmit at a given time. In addition, the AP may also perform beamforming by running chains off of spatially diverse antennas and adding well adjusted phases, thereby focusing the energy on the client/node. Doing so improves the range and/or the signal quality, while also limiting the interference on others.

Each VAP may reside on a given wireless channel and is comprised of a collection of AP radios chains positioned in the area of the location of the client. When the system expands at the scale of the entire floor, a large number of radios, all positioned on the same channel, represent a limiting factor for the channel efficiency. Multiple clients at different locations on the floor share the same radio frequency (RF) collision domain, increasing the risk of frame collisions and co-channel interferences between transmitters. The entire structure may also become limited to the lowest common number of radio chains. For example, a collection of APs with four radio chains may end up creating four layers of VAPs available at the scale of the entire floor, effectively limiting the system to four VAPs.

Traffic and Mobility Aware VAPs

The techniques herein introduce mechanisms to allocate a VAP in a network based on the device mobility and traffic types of a client node. In some aspects, VAPs may be formed around nodes taking into account their mobility characteristics. For example, large, “floor-wide,” or “regional” VAPs may be formed for nodes expected to move about the floor, while “local island” VAPs may be formed for more local/static nodes. In further aspects, the traffic volume of a node may also be taken into account, to further allocate a VAP based on the expected traffic volume of a node and channel utilization of a given wireless channel, thus increasing the channel reuse potential.

Specifically, according to one or more embodiments of the disclosure as described in detail below, a supervisory device in a network classifies mobility and traffic characteristics of a first node in the network. The supervisory device identifies wireless channels supported by access points (APs) in the network. The supervisory device selects one of the wireless channels for use by the first node based on the classified mobility and traffic characteristics of the first node. The supervisory device forms a first virtual access point (VAP) for the first node on the selected wireless channel. A plurality of the access points (APs) in the network that support the selected channel are mapped to the first VAP as part of a VAP mapping. The first node treats the APs in the VAP mapping as a single AP for purposes of communicating with the network.

Illustratively, the techniques described herein may be performed by hardware, software, and/or firmware, such as in accordance with the VAP process 248, which may include computer executable instructions executed by the processor 220 (or independent processor of interfaces 210) to perform functions relating to the techniques described herein, e.g., in conjunction with routing process 244.

Operationally, the techniques herein introduce the concept of VAP allocation based on client type, such as the on the mobility behavior and traffic fingerprinting of a node). Each AP may have multiple radio chains, whereby the number of radio chains constitutes the local resource set of the AP. Accordingly, each VAP may comprise one or more radio chains. The number of radio chains allocated to a given channel (and therefore a given VAP), or available to be allocated to a given channel (available resource) determines the VAP potential coverage.

A VAP with more allocated radio chains (currently allocated, or available on APs across the floor, and therefore potentially allocated) has a larger coverage than an AP with a lower number of allocated (effectively or potentially) radio chains. In addition, each VAP channel also has a measurable load, which may be modeled by its channel utilization (CU).

In various embodiments, the supervisory device overseeing the APs may determine a channel plan whereby the channels are set based on the type of mobility of known associating clients and the type of traffic volume that these clients are expected to require. For example, as shown in FIG. 6, assume that there are nodes 306 a-306 c, each having different mobility and traffic characteristics. In such a case, supervisory device 304 may devise a channel plan across the APs 302 a-302 j based on the mobility and traffic characteristics of nodes 306 a-306 c. Several classifications are possible for nodes 306 a-306 c such as, but not limited to:

-   -   A typology based on the traffic volume exchanged with each         client type, ranging from heavy talkers to low talkers (e.g.,         high volume clients to low volume clients).     -   A typology based on the mobility behavior of each client type,         ranging from high mobility clients to stationary/static clients,         across an entire floor or a determined area/set of APs.

In one embodiment, the VAP channel, and consequently the AP members of the VAP, is allocated to a client based on its mobility. For example, supervisory device 304 may assign a high roamer a wireless channel associated with radios set at high power, leading to a larger coverage range for individual radios, but used by a lower density of APs in the area (e.g., there may be a lower number of APs that support this channel in a given area). Conversely, supervisory device 304 may assign a low roamer or static client to a channel associated with only local radios (e.g., within close proximity of the node), leading to a comparatively smaller coverage range for the entire VAP. However, doing so also allows for the opportunity for the channel to be used elsewhere, such as at multiple points on the floor (e.g., at distances where co-channel interference ceases to be a major source of interferences), thus creating the potential of multiple “islands” of different VAPs using the same channel number without cross-interference.

In various embodiments, supervisory device 304 may leverage machine learning, to optimize the channel plan, AP assignments, and/or speeds of receiving APs based on an objective function. For instance, one frequency/channel may be defined for a local area and allowed a maximum channel utilization capacity based on known node behaviors.

A consequence of the above optimization mechanism is that multiple channels (and VAPs) become available for various client nodes. The VAP system may build multiple “local” islands (e.g., on the same or different channels), some VAPs of “regional” (part of the floor) coverage, and/or some VAPs of “floor wide” coverage. Some VAPs may consist of radios chains at close range of one another, resulting in a dense radio system around the client location with a potential of strong radio signal to and from the client. Other VAPs may consist of radios chains far apart from each other, resulting in a low density of radios that still provide a wide range of coverage, but with the potential of lower radio signal to and from the client nodes.

In some embodiments, the supervisory device may combine the mobility behavior of the node with a coverage to CU ratio, to determine the VAP and channel that best matches the roaming behavior of the client node, and the expected traffic exchanged with that node. For example, as shown in FIG. 7A, assume that the APs 302 report data 310 to supervisory device 304 regarding node 306. Such data may be indicative of the mobility of node 306 (e.g., how the client node is moving about in the physical location) and the traffic characteristics of node 306, such as the bandwidth consumed by the traffic associated with node 306 and/or the type of traffic (e.g., media traffic, etc.).

As shown in FIG. 7B, based on the received data 310, supervisory device 304 may classify the mobility of node 306 as falling within a predefined category, such as “high mobility,” “moderate mobility,” “low/static mobility,” or the like. In addition, supervisory device 304 may also classify the traffic characteristics of node 306 based on the gathered information about node 306, such as being “high bandwidth,” “moderate bandwidth,” “low bandwidth,” etc. Notably, for illustrative purposes, assume that supervisory device 304 classifies node 306 as having a high bandwidth requirement, but does not move, physically. For example, node 306 may be a static video camera that does not change its physical location.

As shown in FIG. 7C, based on the mobility and traffic characteristics of node 306, supervisory device 304 may assign node 306 to a particular wireless channel supported by one or more nearby APs 302, thereby forming a VAP with low channel utilization but of only local significance (e.g., a local “island”). For example, assume that AP 302 c may use a wireless channel that has relatively low floor coverage, but supports higher bandwidths. Even though AP 302 c may have a lower signal quality than that of APs 302 f-302 g, supervisory device 304 may nonetheless assign node 306 to AP 302 c based on its objective function determining that AP 302 c offers the best CU and smallest footprint around node 306 (e.g., best coverage/CU for that client node type).

FIGS. 8A-8B illustrate another example of the formation of a VAP based on the mobility and traffic characteristics of a client node, in further embodiments. In the example shown in FIG. 8A, assume that supervisory device 304 instead determines that node 306 has a high bandwidth requirement, but is also highly mobile. In such a case, as shown in FIG. 8B, supervisory device 304 may assign AP 302 g to the VAP of node 306, even though AP 302 f offers the highest link quality. Notably, AP 302 g may offer better metrics in terms of a floor coverage*(1/CU) index than that of AP 302 f, leading supervisory device 304 to select AP 302 g for inclusion in the VAP for node 306.

In further embodiments, the VAP characteristics can be temporarily altered to match the target requirements of the client node. For example, radio chains participating to a “local island” VAP to cover a static node with medium expected traffic volume may reduce their transmission power to match the traffic needs of the node. Reducing the transmission power mechanically reduces the signal at a distance, and therefore mechanically forces the node, at that distance, to use a lower modulation and coding scheme (MCS). The participating radio chains may also indicate allowed or forbidden MCSs. Forbidding low MCSs mechanically reduces the distance at which the VAP is usable. Combining transmission power adjustments, together with allowed MCSs, allows the participating radios to tailor the VAP to the supported traffic pattern and volume of the node, covering the physical area (but no more) of the node, and offering MCSs that match the throughput needed by the node (but no less).

This power and MCS allocation can also be dynamic, in some cases. For example, a highly mobile and high talker client node can be allocated to a “regional” or “floor-wide” VAP (based on the span of movement of the node), and the associated VAP characteristics can be tuned to adapt to the needs reflected by the station type (e.g., higher transmission power, larger range of allowed MCSs to match faster movements of the node). The result of this scheme is a dynamic set of VAPs which width and channel characteristics match the needs of the client node, while offering both the largest “channel coverage to channel utilization” and “channel coverage to channel reuse potential” ratio.”

FIG. 9 illustrates an example simplified procedure for forming a traffic and mobility aware VAP, in accordance with one or more embodiments described herein. For example, a non-generic, specifically configured device (e.g., device 200), such as a supervisory device that oversees one or more APs, may perform procedure 900 by executing stored instructions (e.g., process 248). The procedure 900 may start at step 905, and continues to step 910, where, as described in greater detail above, the supervisory device may classify mobility and traffic characteristics of a first client node in the network. In various embodiments, the mobility characteristics may be determined based on the location-related information regarding the node (e.g., APs in communication proximity, RSSI information, other location information, etc.). Such characteristics can be used to categorize the node as being one of “high mobility,” “low mobility,” etc. In further embodiments, the traffic characteristics may be categorized as requiring “high bandwidth,” “low bandwidth,” etc. Additionally, in some cases, the supervisory device may also consider and classify the type of traffic, such as “media,” “data traffic,” etc.

At step 915, as detailed above, the supervisory device may identify wireless channels supported by APs in the network. Typically, a given AP may have one or more radio chains and may use each chain for a different channel or, alternatively, multiple chains for a single channel, such as in the case of beamforming. Each channel may also have a measurable amount of channel utilization that the supervisory device may determine.

At step 920, the supervisory device may select one of the wireless channels for use by the first node based on the classified mobility and traffic characteristics of the first node. For example, in various embodiments, the supervisory device may select wireless channels for different client nodes as part of an optimized channel plan. Notably, the supervisory device may use machine learning to assign different nodes to different wireless channels, while taking into account the traffic and mobility characteristics of the nodes, as well as the characteristics of the channels (e.g., their channel utilizations, transmission powers, ranges, etc.). For example, if the node is found to be of low mobility, it may be assigned to a wireless channel in use by one or more APs near the node that uses a comparatively low transmission power. Doing so allows the supervisory device to assign the same channel for use by other nodes/VAPs in different parts of the location. Conversely, if the node is highly mobile, the supervisory device may assign the node to a channel that has significant area coverage, such as “floor wide” coverage.

At step 925, as detailed above, the supervisory device may form a first virtual access point (VAP) in the network for a first node on the selected channel. A plurality of access points (APs) in the network that support the channel are mapped to the VAP and the APs in the VAP mapping are treated as a single AP by the node for communicating with the network. Procedure 900 then ends at step 930.

It should be noted that while certain steps within procedure 900 may be optional as described above, the steps shown in FIG. 9 are merely examples for illustration, and certain other steps may be included or excluded as desired. Further, while a particular order of the steps is shown, this ordering is merely illustrative, and any suitable arrangement of the steps may be utilized without departing from the scope of the embodiments herein.

The techniques described herein, therefore, allow for the use of a VAP in a network, while also taking into account the movement and traffic patterns of client nodes. When each client type operates on a separate SSID without such an assignment structure, clients traffic pattern may result in either channel under-utilization (e.g., when clients with low traffic occupy a channel) or channel saturation (e.g. when several clients of the same type and high traffic volume coexist on the same physical space). Additionally, client movement dictates whether a given SSID has to spread over a large (whole floor) or a small space.

While there have been shown and described illustrative embodiments that provide techniques related to virtual access points (VAPs), it is to be understood that various other adaptations and modifications may be made within the spirit and scope of the embodiments herein. For example, while certain embodiments are described herein with respect to using certain environments, such as the IoT, other embodiments need not be limited to IoT devices. In addition, while certain protocols are shown, such as Wi-Fi, 802.15.4, LoRa, etc., other suitable protocols may be used, accordingly. For instance, while the techniques herein generally apply to a generalized CSMA/CA LLN, it should be specifically noted that the techniques can be applied to (based on) any of the standards mentioned above or known in the art. For ease of understanding (expecting the reader to be more familiar with the Wi-Fi parlance), the description above uses the term AP in the more general sense of a transceiver in a network. However, with Bluetooth LE, the central role illustratively maps to an AP, whereas the peripheral role is akin to the endpoint node. The same goes for the 802.15.4 PAN coordinator which is similar to an AP, and the full-function device (FFD) or reduced-function device (RFD) which illustratively map to an endpoint node, when 802.15.4 is used in plain hub-and-spoke (in that case a PAN ID illustratively serves as SSID). With DECT-ULE, the DECT Fixed Part is illustratively the AP, and the Portable Part is illustratively the node.

Note that some protocols on Wi-Fi networking refer to a “virtual access point” as many different things. For example, hosting several logical APs in one physical AP may be referred to as a “virtual access point”, while turning a PC into an AP may also be referred to as a “virtual access point”. The VAPs in this present disclosure should not be confused with the shared terminology, and is completely different in that one VAP herein is distributed over multiple physical APs, and there can be one VAP per STA.

The foregoing description has been directed to specific embodiments. It will be apparent, however, that other variations and modifications may be made to the described embodiments, with the attainment of some or all of their advantages. For instance, it is expressly contemplated that the components and/or elements described herein can be implemented as software being stored on a tangible (non-transitory) computer-readable medium (e.g., disks/CDs/RAM/EEPROM/etc.) having program instructions executing on a computer, hardware, firmware, or a combination thereof. Accordingly this description is to be taken only by way of example and not to otherwise limit the scope of the embodiments herein. Therefore, it is the object of the appended claims to cover all such variations and modifications as come within the true spirit and scope of the embodiments herein. 

What is claimed is:
 1. A method comprising: classifying, by a supervisory device in a network, mobility and traffic characteristics of a first node in the network; identifying, by the supervisory device, wireless channels supported by access points (APs) in the network; selecting, by the supervisory device, one of the wireless channels for use by the first node based on the classified mobility and traffic characteristics of the first node; and forming, by the supervisory device in a network, a first virtual access point (VAP) for the first node on the selected wireless channel, wherein a plurality of the access points (APs) in the network that support the selected channel are mapped to the first VAP as part of a VAP mapping, and wherein the first node treats the APs in the VAP mapping as a single AP for purposes of communicating with the network.
 2. The method as in claim 1, wherein the APs are Wi-Fi access points.
 3. The method as in claim 1, wherein the mobility of the first node is classified as high mobility, and wherein the plurality of APs in the VAP mapping have comparatively higher coverage on the selected channel than that of other APs in the network.
 4. The method as in claim 1, wherein the mobility of the first node is classified as low mobility, and wherein the plurality of APs in the VAP mapping have comparatively lower coverage on the selected channel than that of other APs in the network.
 5. The method as in claim 4, further comprising: forming, by the supervisory device, a second VAP on the selected wireless channel for a second node in the network, wherein a second set of APs in the network that support the selected channel are mapped to the second VAP as part of a second VAP mapping, and wherein the APs in the first VAP mapping are out of range of the APs in the second VAP mapping.
 6. The method as in claim 1, wherein the traffic characteristics of the first node are indicative of expected traffic volumes associated with the node, and wherein the wireless channel is selected based in part on a channel utilization of the channel.
 7. The method as in claim 1, wherein the APs in the VAP mapping for the first VAP exclude an AP in the network with which the first node has the best link quality.
 8. The method as in claim 1, further comprising: adjusting, by the supervisory device, a physical area of coverage for the first VAP by controlling which modulation coding schemes (MCSs) can be used by the first node.
 9. The method as in claim 1, wherein selecting the wireless channel for use by the first node based on the classified mobility and traffic characteristics of the first node comprises: using, by the supervisory device, a machine learning-based model to determine an optimal channel plan for the APs in the network, to form a plurality of VAPs for a plurality of nodes in the network.
 10. An apparatus, comprising: one or more network interfaces to communicate with a network; a processor coupled to the network interfaces and configured to execute one or more processes; and a memory configured to store a process executable by the processor, the process when executed configured to: classify mobility and traffic characteristics of a first node in the network; identify wireless channels supported by access points (APs) in the network; select one of the wireless channels for use by the first node based on the classified mobility and traffic characteristics of the first node; and form a first virtual access point (VAP) for the first node on the selected wireless channel, wherein a plurality of the access points (APs) in the network that support the selected channel are mapped to the first VAP as part of a VAP mapping, and wherein the first node treats the APs in the VAP mapping as a single AP for purposes of communicating with the network.
 11. The apparatus as in claim 10, wherein the APs are Wi-Fi access points.
 12. The apparatus as in claim 10, wherein the mobility of the first node is classified as high mobility, and wherein the plurality of APs in the VAP mapping have comparatively higher coverage on the selected channel than that of other APs in the network.
 13. The apparatus as in claim 10, wherein the mobility of the first node is classified as low mobility, and wherein the plurality of APs in the VAP mapping have comparatively lower coverage on the selected channel than that of other APs in the network.
 14. The apparatus as in claim 13, wherein the process when executed is further configured to: form a second VAP on the selected wireless channel for a second node in the network, wherein a second set of APs in the network that support the selected channel are mapped to the second VAP as part of a second VAP mapping, and wherein the APs in the first VAP mapping are out of range of the APs in the second VAP mapping.
 15. The apparatus as in claim 10, wherein the traffic characteristics of the first node are indicative of expected traffic volumes associated with the node, and wherein the wireless channel is selected based in part on a channel utilization of the channel.
 16. The apparatus as in claim 10, wherein the APs in the VAP mapping for the first VAP exclude an AP in the network with which the first node has the best link quality.
 17. The apparatus as in claim 10, wherein the process when executed is further configured to: adjust a physical area of coverage for the first VAP by controlling which modulation coding schemes (MCSs) can be used by the first node.
 18. The apparatus as in claim 10, wherein the apparatus selects the wireless channel for use by the first node based on the classified mobility and traffic characteristics of the first node by: using a machine learning-based model to determine an optimal channel plan for the APs in the network, to form a plurality of VAPs for a plurality of nodes in the network.
 19. A tangible, non-transitory, computer-readable medium storing program instructions that cause a supervisory device in a network to execute a process comprising: classifying, by the supervisory device, mobility and traffic characteristics of a first node in the network; identifying, by the supervisory device, wireless channels supported by access points (APs) in the network; selecting, by the supervisory device, one of the wireless channels for use by the first node based on the classified mobility and traffic characteristics of the first node; and forming, by the supervisory device in a network, a first virtual access point (VAP) for the first node on the selected wireless channel, wherein a plurality of the access points (APs) in the network that support the selected channel are mapped to the first VAP as part of a VAP mapping, and wherein the first node treats the APs in the VAP mapping as a single AP for purposes of communicating with the network.
 20. The tangible, non-transitory, computer-readable medium as in claim 19, wherein the APs in the VAP mapping for the first VAP exclude an AP in the network with which the first node has the best link quality. 